Dynamic Liquid Measurement Calculations
Scott Tanner Flow-Cal, Inc.
Chapter 12 - Calculation of Petroleum Quantities
• Section 1 – Calculation of Static Petroleum Quantities
• Section 2 – Calculation of Petroleum Quantities Using Dynamic Measurement Methods and Volumetric Correction Factors
• Section 3 – Calculation of Volumetric Shrinkage from Blending Light Hydrocarbons with Crude Oil
Chapter 12.2 Organization
• Part 1 – Introduction • Part 2 – Measurement Tickets • Part 3 – Proving Reports • Part 4 – Calculation of Base Prover
Volumes by the Waterdraw Method • Part 5 – Calculation of Base Prover
Volume by Master Meter Method
Chapter 12.2.x Applicable Liquids
• Hydrocarbon Liquids • Which are Considered to be Clean • Single-Phase • Homogeneous • Newtonian at Metering Conditions
Chapter 12.2.x Density Types
• Base or Standard Condition • Observed Condition • Alternate Conditions
Distinction Between “Base” and “Standard” Condition
• “Base” or “Standard” Condition – is a defined temperature and pressure at which liquid volumes are corrected for custody transfer purposes. – The terms Base and Standard are used
interchangeably.
Chapter 12.2.x Base Conditions • United States Customary (USC) Units:
– Temperature (Tb): 60.0°F (15.56°C) – Pressure (Pb): 14.696 psia (101.325 kPaa)
• International System (SI) Units: – Temperature (Tb): 15.0°C (59.0°F) or 20.0°C (68.0°F) – Pressure (Pb): 101.325 kPaa (14.696 psia)
• For Liquids with an Equilibrium Vapor Pressure (EVP) > Base Pressure (Pb), the (Pb) shall be the EVP at Base Temperature (Tb)
Distinction Between “Observed,” and “Alternate” Conditions
• “Observed” Condition – is the temperature and
pressure at which the density of a liquid is actually measured – Density Meter or Hydrometer Condition
• “Alternate” Conditions – are any other temperature and pressure conditions to which the observed or standard density can be corrected – Metering or Tank Condition
Commodity Types • A = Crude Oil • B = Refine Product • C = Special Application • D = Lubricating Oil
API Chapter 11.1 uses Three Distinct “Calculation Types”
• Type 1. Starts with “Base” density and corrects it to an alternate temperature and pressure condition using CTL & CPL – Procedures:
• 11.1.6.1 (USC) & 11.1.7.1 (SI) – Functions:
• densA11161API & densA1161RelDens • ctplB11161API & ctplB11161RelDens • fpC11161API & fpC11161RelDens • densD11171kPa & densD1171Bar • ctplA11171kPa & ctplA11171Bar • fpB11171kPa & fpB11171Bar
API Chapter 11.1 uses Three Distinct “Calculation Types”
• Type 2. Starts with “Observed” density at its temperature & pressure and corrects it to base condition using CTL & CPL – Procedures:
• 11.1.6.2 (USC) & 11.1.7.2 (SI) – Functions:
• densB11162API & densB1162RelDens • ctplC11162API & ctplC11162RelDens • fpD11162API & fpD11162RelDens • densA11172kPa & densA1172Bar • ctplB11172kPa & ctplB11172Bar • fpC11172kPa & fpC11172Bar
API Chapter 11.1 uses Three Distinct “Calculation Types”
• Type 3. Starts with “Observed” density at its temperature & pressure and corrects it to an “Alternate” temperature & pressure condition Procedures:
• 11.1.6.3 (USC) & 11.1.7.3 (SI) – Functions:
• densA11162API > ctplA11161API • densB11162RelDens > ctplB11161RelDens • dens1C1162API > fpC11161API • densD11172kPa > ctplD11171kPa • densA11172Bar > ctplA11171Bar • densC11172kPa > fpC11161kPa
Chapter 12.2.x Step 1 – Determine Base Density (RHOb)
• Use an API 11.1 – Type 2 Density Calculation – API 11.1 Procedure 11.1.6.2 for USC Unit – API 11.1 Procedure 11.1.7.2 for SI Units
• Enter “Observed” density at its observed temperature and pressure – RHOobs (XXX.x °API, X.xxx5 RD or XXXX.5 kg/m3) – Tobs ( XXX.x °F or XX.x5 °C) – Pobs (XXXX.0 psig or XX.xxx bar or XXXX.0 kPa) – Tb (15.0 or 20.0°C for SI Units only)
Determine Base Density (RHOb)
Chapter 12.2.x Step 2 – Are the Meter Readings Temperature Compensated?
• If “Yes” Go To Step 3a • If “No” Go To Step 3b
Chapter 12.2.x Step 3a – Determine Temperature Correction Factor (CTL) • Set CTL = 1.0000
Chapter 12.2.x Step 3b – Determine Temperature Correction Factor (CTL) • Use an API 11.1 – Type 1 Calculation
– API 11.1 Procedure 11.1.6.1 for USC Unit – API 11.1 Procedure 11.1.7.1 for SI Units
• Enter the base density at the meter’s flow weighted temperature and pressure – RHOb (XXX.x °API, X.xxxx RD or XXXX.x
kg/m3) from Step 1 – TWA ( XXX.x °F or XX.x5 °C) – PWA (XXXX.0 psig or XX.xxx bar or XXXX.0
kPa) – Tb (15.0 or 20.0°C for SI Units only)
Determine CTL
Chapter 12.2.x Step 4 – Are Meter Readings Pressure Compensated?
• If “Yes” – Step 5a • If “No” – Step 5b & 5c
Chapter 12.2.x Step 5a – Determine Pressure Correction Factor (CPL)
• Set CPL = 1.0000
Chapter 12.2.x Step 5b – Determine Scaled Compressibility Factor (Fp)
• Use an API 11.1 – Type 1 calculation – API 11.1 Procedure 11.1.6.1 for USC Unit – API 11.1 Procedure 11.1.7.1 for SI Units
• Enter the base density at the meter’s flow weighted temperature and pressure – RHOb (XXX.x °API, X.xxxx RD or XXXX.x kg/m3) – TWA ( XXX.x °F or XX.x5 °C) – PWA (XXXX.0 psig or XX.xxx bar or XXXX.0 kPa) – Tb (15.0 or 20.0°C for SI Units only)
Step 5b – Determine F
Where: • ρ = Base Density • T = Flow Weighted Temperature
( )2
79320.0 2326.0*exp 1.9947 0.00013427
TF
ρ
+ = − + +
Determine Fp
Chapter 12.2.x Step 5c – Determine CPL
• Use an API 11.1 – Type 1 calculation – API 11.1 Procedure 11.1.6.1 for USC Unit – API 11.1 Procedure 11.1.7.1 for SI Units
• Enter the base density at the meter’s flow weighted temperature and pressure – RHOb (XXX.x °API, X.xxxx RD or XXXX.x kg/m3) – TWA ( XXX.x °F or XX.x5 °C) from Step 1 – PWA (XXXX.0 psig or XX.xxx bar or XXXX.0 kPa) – Tb (15.0 or 20.0°C for SI Units only)
Step 5c – Determine CPL
Where: • F = Scaled Compressibility Factor • PWA = Flow Weighted Pressure • Pe = Equilibrium Vapor Pressure
( )5
11 10 * * e
CPLF PWA P−=
− −
Determine CPL
Chapter 12.2.x Step 6 – Determine Combined Correction Factor (CCF)
• CCF = (CTL) * (CPL) * (MF) X.xxxx – If a Meter Factor (MF) is Used
• CCF = (CTL) * (1.0000) * (CMF) X.xxxx – If a Composite Meter Factor (CMF) is Used
• CCF = (CTL) * (CPL) * (1.0000) X.xxxx – If an “Actual” K-Factor (KF) is used
• CCF = (CTL) * (1.0000) * (1.0000) X.xxxx – If a Composite K-Factor (CKF) is used
Determine CCF
Chapter 12.2.x Step 7 – Determine Indicated Volume (IV)
• IV = MRc – MRo – Barrels & Gallons = XXX.xx – Cubic Meter = XXX.xxx – Liter = XXX.0
where: – IV = Indicated Volume – MRc = Meter Reading Closed – MRo = Meter Reading Opened
Determine Indicated Volume (IV)
Chapter 12.2.x Step 8 – Determine Gross Standard Volume (GSV)
• GSV = IV * CCF – Barrels & Gallons = XXX.xx – Cubic Meter = XXX.xxx – Liter = XXX.0
where: – GSV = Gross Standard Volume – IV = Indicated Volume – (Step 7) – CCF = Combined Correction Factor – (Step 6)
Determine GSV
Chapter 12.2.x Step 9 – Determine Sediment & Water Correction Factor
where: – CSW = Correction for Sediment and Water – %S&W = Sediment and Water Percent
1 (% & /100)CSW S W= −
Determine CSW
Chapter 12.2.x Step 10 – Determine Net Standard Volume (NSV)
• NSV = GSV * CSW – Barrels & Gallons = XXX.xx – Cubic Meter = XXX.xxx – Liter = XXX.0
where: – NSV = Net Standard Volume – GSV = Gross Standard Volume – (Step 8) – CSW = Sediment & Water Correction Factor – (Step 9)
Determine NSV
Chapter 12.2.x Step 11 – Determine Sediment & Water Volume (SWV)
• SWV = GSV - NSW – Barrels & Gallons = XXX.xx – Cubic Meter = XXX.xxx – Liter = XXX.0
where: – SWV = Sediment and Water Volume – NSV = Net Standard Volume (Step 10) – GSV = Gross Standard Volume – (Step 8)
Determine SWV